My First Workbench Build - A Journal

[Robert Engel]

Eric, with a captured bolt you don't need a tenon deeper than 1". The shoulders are more important I would leave 1" top and bottom and 1/2" on the sides.

Both workbenches I built this way when you tighten up those bolts its quite sturdy. Personally, I would question whether a 3x3 stretcher is wide enough. Maybe you don't need to with the through tenon legs, but it seems to me a 5-6" wide stretcher would be more sturdy. The stretchers on my big bench are 2x8 with a 1x6 mortise.

A flat bottom be achieved with a Forstner bit then just clean up the corners and sides (or round over the tenons).